混流式水轮机空化流动模拟中的空化模型对比研究

以某水电厂混流式机组为例,在同样的工况下,采用Schnerr-Sauer空化模型和Z-G-B空化模型对其进行空化流动模拟,并与现场真机试验情况进行对比,从而比较各模型的计算效果。结果表明,水轮机叶片背面进水边、出水边附近的大部分区域、水轮机叶片下半段与下环交界处的空化程度较为严重。此外,Schnerr-Sauer空化模型仅适用于空泡数量比较少的情形,且仿真效果不甚理想;而Z-G-B模型的适用范围较广,且效果较好,因此可以在混流式水轮机空化流动模拟中更多地采用。

Comparative study on cavitation models applied to simulation of cavitation flow in francis turbine

By taking a Francis turbine generating unit in a hydropower plant as the actual case，Schnerr-Sauer cavitation model and Z-G-B cavitation model are adopted to simulate the cavitation flow in it under the same operation conditions，from which the results are compared with that from the field prototype test，thus the calculation effects of both the models are compared. The result shows that the cavitation degrees are more serious at a large area near the water inlet and outlet brims on the back of the turbine blade，the lower part of the turbine blade and the location in junction with the low-ring. Moreover，Schnerr-Sauer cavitation model is only suitable for the case with less cavitation bubbles and then the simulation effect is not so ideal，while the applicable range of Z-G-B cavitation model is wider，thus can be frequently applied to the simulation of the cavitation flow in Francis turbine.